1. Field of the Invention
This invention relates to a vessel that facilitates gas stirring of molten metal and a method of mixing in molten metal a material that tends to settle.
2. Prior Art
A variety of vessels are known for containing molten metal and facilitating the introduction of gas for a variety of purposes. See, for example, the U.S. Pat. Nos. 506,328 to Morris; Gesner 604,580; Langguth 1,169,270; Moore 1,763,248; Dreyfus 2,513,082; Drummond 2,826,494; Leroy et al. 2,975,047; Leroy et al. 3,062,524; Goedecke et al. 3,208,117; Andrzejak et al. 3,684,267; Andrzejak et al. 3,809,146; Shapland 3,825,241; and Voss 3,838,798.
Vessels such as those disclosed in the above referenced patents are not particularly suitable for specific use in mixing or stirring molten metal when material to be mixed tends to settle from the molten metal after being added but prior to being poured, as when dissolution is incomplete or slow, or for discharging molten metal from a bottom opening when undissolved material which should not be discharged may have settled. In particular, the vessels disclosed are not particularly suitable for gas stirring and mixing lead additions or the like, into steel. As the above prior art indicates, gas has been injected into molten metal to mix material on top of the metal bath in a furnace (U.S. Pat. No. 1,763,248), and alloying additions have been introduced as a gas through a porous plug (U.S. Pat. No. 2,826,494). Such structures fail to facilitate effectively mixing additions in a molten bath through gas stirring, where the additions tend to settle and must be re-entrained into the molten metal for further dispersion and/or dissolution.